Ink is failing to form a continuous film

Adjust ink to reduce viscosity. Use a more active (wetter) solvent

Stock is too rough

Use electro-assist (with polar solvents)

There are imperfections in the stock

Adjust doctor blade to carry more ink. Use coating primer if possible

The ink is wrong for the substrate

Reformulate or replace ink

Film treatment is poor

Retreat or replace film

Worn cylinder, insufficient film transfer to cover substrate

Re-make cylinder